Wash ammonia development device



Jan; 23, 1968 R. B. MULVANY 3,

WASH AMMONIA DEVELOPMENT DEVICE Filed Feb. 5, 1965 I/Vl/E/VTOR RICHARD B. MULVA NY United States Patent 3,364,833 WASH AMMONIA DEVELOPMENT DEVICE Richard B. Mulvany, San Jose, Calif., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed Feb. 3, 1965, Ser. No. 430,094 8 Claims. (Cl. 95-89) ABSTRACT OF THE DISflLOSURE and entrapped air takes place so that efficient sweeping or washing of air out of the development chamber occurs.

This invention relates in general to a development method and apparatus wherein developer fluids or gasses are presented at pressures greater than ambient to a member to be developed and more particularly to a development method and apparatus for developing a film surface in a sealed development device by purging the air trapped .therein by means of the developer fluid.

In United States patent application Ser. No. 369,861, entitled, Diazo Development Process, assigned to the assignee of the present application, there is provided a development process which enables the development of ammonia sensitive films such as diazo in a fraction of a second. This process, simply stated, involves applying the developing ammonia to the surface to be developed at a relatively high pressure, such as for instance, 90 p.s.i.g. Obviously, to utilize this process, tight developer platen to film sealing is necessary.

Experience with the high pressure ammonia development process has demonstrated non-uniform image development when the necessary tight developer platen to film sealing is achieved. This non-uniformity often includes film areas that appear completely undeveloped even to the naked eye while adjacent film areas appear to be fully developed. This non-uniformity of development is due to the entrapment of air between the film surface and the developer platen at the time the film is sealed to the developer platen.

Several solutions to this problem of entrapped air are available. Mixing of the air and ammonia is one of the more obvious. However, it is diflicult to achieve uniform mixing in a thin cavity in a short period of time.

While the development time may be extended to assure development of all film areas, a significant increase in the development time (2x or more) is required to achieve even limited improvement. The attempt to avoid underdeveloped areas by increasing the development period both compromises the high speed advantage of the process and overdevelops most of the film image area. Overdevelopment may not change the photometric properties of a developed image, but, by increasing the total quantity of ammonia absorbed by the film, it causes both ammonia consumption and the quantities of ammonia subsequently released by the film to be increased. This excessive absorption of ammonia associated with overdevelopment may, particularly with acetate base film 3,364,833 Patented Jan. 23, 1968 materials, also cause deleterious mechanical effects such as film curl.

Another solution to the problem is evacuation of the entrapped air. If a developer platen is evacuated after sealing, and before the introduction of ammonia, by special valving and vacuum source means, non-uniformity due to air entrapment can be avoided. The evacuation approach obviously suffers from increased machine complexity.

Uniform development may a so be achieved by permitting some leakage at the film to developer seal so that the entrapped air is forced out of the platen cavity by the introduction of ammonia. Developer platens have been built using this controlled leak seal approach. Uniform development has been achieved with both metal to film seals and elastomer to film seals where the entire seal periphery permitted some leakage. This approach suffers from the fact that the air is followed by ammonia gas which not only is highly corrosive, but, additionally, is poisonous in relatively low concentrations.

It is therefore an object of the present invention to provide a novel method of utilizing the high pressure ammonia development process with minimum ammonia consumption.

Another object of the present invention is to provide a new method of uniform image development of a film area sealed to a high pressure ammonia developer platen where entrapped air is present at the instant of ammonia introduction, and where the entrapped air is removed from the surface of the image area by other than evacuation or controlled leakage by a wash development method.

Another object of the present invention is to provide a new development device suitable for use in the wash development process wherein entrapped air is swept by means of incoming ammonia into an entrapment cavity.

Other and further objects and advantages of the invention will be apparent from the following more particular description of the preferred embodiment of the invention as illustrated in the accompanying drawings in which:

FIG. 1 is an exploded perspective view of the preferred embodiment of the development device;

FIG. 2 is a cutaway side view taken along lines 4-4 of FIG. 1.

Briefly, for accomplishing the subject method of development, there is provided a novel developer device wherein an air entrapment port is provided in the development chamber at a point distant from the ammonia injection port such that the entering ammonia sweeps the thin layer of entrapped air ahead of it into an air entrapment cavity which results in a high concentration of ammonia being presented to the film surface or area. In this method, it is important that the development chamber be relatively thin such that a minimum amount of mixing between the entering ammonia and entrapped air takes place so that efficient sweeping or washing of air out of the development chamber occurs. Additionally, the ports for entrance of ammonia and escape of the entrapped air should be geometrically placed such that the entire film surface is washed.

An optimum developer design should permit the purging of the entrapped air from the development chamber in combination with a narrow seal area adjacent to the edge of the image area and an integral air entrapment cavity completely removed from the film surface. Such a design permits uniform development of image areas with edges close to the outside dimension of a film chip, or the close spacing of posted images to a film surface where the individual images are developed at different times.

FIGS. 1 and 2 show a developer assembly 18 with an integral entrapped air cavity 15 placed at the rear of the baffle plate 16 away from the film surface 17. The

developer assembly 18 is made up of a seal plate 19, with an O-ring seal 30 and the diffuser plate 16. The difiuser plate 16 is inserted into the seal plate 19 to provide a low volume platen cavity or development chamber 33 approximately .003" high between the top 20 of the diffuser plate 16 and the film emulsion surface 17 when the film 13 carried in an aperture card 14 is pressed against the seal plate surface 21 by the action of the flat closure platen 22. The diffuser plate 16 is fitted tightly to the sides 23 and 24 of the seal plate 19 but spaced from the ends to provide a first or inlet port 25 and a second port 26. These ports are elongated slots extending across the width of the chamber. The diffuser plate 16 incorporates a .002"-.004 high relief 27 on its lower or rear surface to provide a passage from the ammonia supply valve entrance 28 to the first port 25. Similarly, the diffuser plate incorporates a .0O4".006 relief 29 on the opposite end of its rear surface to provide a connection for the second port 26 and the cavity 15. Means such as screws 31 hold the diffuser plate 16 to the seal plate 19.

The opening of supply valve 32 permits ammonia to enter through the first port 25 across the full width of the image field and provides relatively uniform flow of ammonia across the image width to Wash or sweep the entrapped air out the second port 26 at the opposite end of the image field. The cavity which also includes second port 26 and passage 29 at the rear of the plate 16 is approximately equal to the volume of the development chamber formed by the top surface and the bafile plate 16, the elastomer seals 30, the film surface 17 and the supply passage 27 to the ammonia supply valve 32. This design was successfully tested with aperture cards utilizing a 2-4 mil clearance between the top 20 of the diffuser plate 16 and the film emulsion surface 17.

The essential point in constructing the platen or developer assembly 18 is that a flow path be established from the ammonia supply across the full image area of the film 17 to the exit ports to provide the sweeping action by the ammonia of the air out of the development chamber 33 by the anhydrous ammonia.

Since the pressurized volume of the developer chamber from supply valve to reservoir must be released at the end of each development cycle, it is desirable to minimize this volume. The developer assembly of FIGS. 1 and 2 has been successfully tested with aperture cards where the only platen cavity was that provided by the approximately .003 thick mounting step on the laminated IBM 1 type aperture cardthe pressurized gas forcing the film down against the closure platen to provide the platen cavity. Obviously, a small cavity is desirable since a minimum amount of ammonia is required. Additionally, a thin cavity permits more efficient sweeping in that the tendency of the ammonia and air to mix or churn is lessened. The main point, of course, being to make a clean sweep of the entrapped air into the air escapement cavity.

The reservoir should be sized relative to the pressurized volume of the development chamber 33 so that at any given operating pressure some ammonia flow will occur through all reservoir interconnecting ports to assure the removal of all entrapped air before pressure in the air entrapment cavity and the developer chamber equalize.

Some entrapped air will, of course, be held by the reservoir prior to the introduction of pressurized gas. The reservoir may at the end of the development cycle contain some pressurized ammonia gas as well as entrapped air. The reservoir size required and the pressurized gas contained in the reservoir to be disposed of at the end of the cycle can be somewhat reduced if an expandable reservoir is utilized.

An expandable reservoir can be achieved by providing a diaphragm in the reservoir to be deformed as the pressure within thereservoir increases or by means such as a unicellular urethane sponge material which is com- 1 Trademark-International Business Machines Corporation.

pressed with pressure thus expanding the size of the reservoir.

It will also be obvious that a more eificient developer device will result if the distance between the ammonia injection port and the air entrapment port is made equal so that the sweep or removal of air will be completed simultaneously along the air entrapment port to cut down on ammonia wastage.

While this invention has been described in terms of its use as an ammonia developer for diazo films in and out of aperture cards, it has also been successfully applied to the development of diazo treated paper and the use of the word film in the following claims is intended to encompass any photo-sensitive material.

The invention may also be applied to other than diazo film materials and may be used with fluids or gasses other than ammonia.

Additionally, while the preferred embodiment of the invention utilizes a dead end cavity to receive the entrapped air displaced or washed out of the development chamber, the exit port may be connected to a vent line or absorber unit with a restrictor orifice or pulsed valve placed between the exit port and the vent or absorber to limit the flow through said exit port without departing from the basic wash method.

In summary, for accomplishing the subject method of development, there is provided a preferred embodiment wherein an air entrapment cavity 15 is provided integrally with the development chamber 33 at a point distant from the ammonia injection port 25 such that the entering ammonia sweeps the thin layer of entrapped air ahead of it into the entrapment port 26 which results in a good concentration of ammonia being presented to the film surface 17. In this method, it is. important that the development chamber 33 be relatively thin such that a minimum amount of mixing between the entering ammonia and entrapped air takes place so that efficient sweeping or washing occurs. Additionally, the ports 25 and 26, respectively, for entrance of ammonia and escape of the entrapped air should be geometrically laced such that the entire film surface is washed.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in the form and details may b made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. A developer device for applying a substance to an area of a material sensitive thereto comprising:

a film developing platen having a film seal shaped to completely enclose said area,

means for bringing said seal into airtight contact with said material around said area whereby a development chamber is formed by said developing platen, said seal and said area, an air entrapment means which communicates with said development chamber spaced from said area, and means for flowing said substance through said development chamber to force air trapped therein into said air entrapment means. 2. In a developer device for applying a gas to a discrete film area, the combination comprising: a film developing platen with a film seal,

said seal being shaped to completely enclose said film area, a closure platen operative to hold said film area again said seal, a development chamber formed by said developing platen, said discrete film surface area and said seal, an air entrapment cavity, first porting means for introducing gas into said development chamber, and second porting means interconnecting said development chamber and said air entrapment cavity,

said second porting means positioned relative to said first porting means such that when said seal is in contact with said film area and pressurized gas is introduced into said development chamber, entrapped air is forced into said air entrapment cavity.

3. In a developer device for applying a pressurized film developing gas to a discrete film area, the combination comprising:

a film developing platen with a film seal,

said seal being rectangular in shape and completely enclosing said film area,

a closure platen operative to hold said film area against said seal,

a development chamber for-med by said developing platen, said discrete film surface area and said seal, an air entrapment cavity,

first porting means located at an extremity of said development chamber for introducing the pressurized film developing gas into said development chamber, and

second porting means located at an opposite extremity of said development chamber interconnecting said development chamber and said air entrapment cavity,

said second porting means positioned relative to said first porting means such that when said seal is in contact with said film area and pressurized gas is introduced into said development chamber, entrapped air is forced into said air entrapment cavity.

4. In a developer device for applying a pressurized film developing gas to a discrete film area, the combination comprising:

a film developing platen with a film seal,

said seal being shaped to completely enclose said film area,

a closure platen operative to hold said film said seal,

a development chamber formed by said developing platen, said discrete film surface area and said seal, an air entrapment cavity expandable in size responsive to increase gas pressure,

first porting means for introducing the pressurized film developing gas into said development chamber, and

second porting meansinterconnecting said development chamber and said air entrapment cavity,

said second porting means positioned relative to said first porting means such that when said seal is in contact with said film area and pressurized film developing gas is introduced into said development chamber, entrapped expandable air is forced into said air entrapment cavity.

5. A method of developing a rectangular film area sensitive to ammonia by means wherein a development chamber for holding ammonia adjacent the film area to be developed is held in airtight contact with the film area, and wherein prior to the entrance of the ammonia into the development chamber entrapped air at substantially ambient pressure exists in the chamber, said method comprising the steps of:

introducing ammonia under pressure into said development chamber through a first porting means located at one extremity of said development chamber while allowing entrapped air to escape through a second porting means located at the opposite extremity of said development chamber, and continuing the introduction of ammonia and thereby increasing the pressure in said development chamber to at least 90 p.s.i.g., said development process being completed within a fraction of a second.

area against 6. A method of developing a rectangular film area sensitive to ammonia by means wherein a development chamber for holding ammonia adjacent the film area to be developed is held in airtight contact with the film area, and wherein prior to the entrance of the ammonia into the development chamber entrapped air at substantially ambient pressure exists in the chamber, said method comprising the steps of:

introducing ammonia under pressure into said development chamber through a first porting means located at one extremity of said development chamber while allowing entrapped air to escape through a second porting means located at the opposite extremity of said development chamber, and

continuing the introduction of ammonia into said development chamber until the entrapped air is completely Washed from the film area to be developed and the pressure in said development chamber is at least p.s.i.g., said development process being completed within a fraction of a second.

7. A method of developing a film area sensitive to ammonia by means wherein a development chamber for holding ammonia adjacent the film area to be developed is held in airtight contact with the film area, and wherein prior to the entrance of the ammonia into the development chamber entrapped air at substantially ambient pressure exists in the chamber, said method comprising the steps of:

introducing ammonia through an ammonia injection port into said development chamber and allowing entrapped air to be washed into an air escape port geometrically spaced from said ammonia injection port such that the entire film area is contacted by the ammonia, and

continuing the introduction of ammonia into said development chamber until the entrapped air is washed from the film area to be developed and the pressure in said development chamber is at least 90 p.s.i.g., said development process being completed within a fraction of a second.

8. A method of developing a film area sensitive to ammonia by means wherein a development chamber for holding ammonia adjacent the film area to be developed is held in airtight contact with the film area, and wherein prior to the entrance of the ammonia into the development chamber entrapped air at substantially ambient pressure exists in the chamber, said method comprising the steps of:

introducing ammonia through an ammonia injection port into said development chamber and allowing entrapped air to be washed into an air escape port geometrically spaced from said ammonia injection port such that the entire film area is contacted by the ammonia, and

continuing the introduction of ammonia into said development chamber until the entrapped air is washed from the film area to be developed and the pressure in said development chamber is at least 60 p.s.i.g., said development process being completed within a fraction of a second.

References Cited UNITED STATES PATENTS 2,228,562 1/1941 Dieterle -89 3,229,608 1/1966 Stau'b et al. 95-89 FOREIGN PATENTS 341,972 1/ 1931 Great Britain.

NORTON ANSHER, Primary Examiner.

F. L. BRAUN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,364,833 January 23, 1968 Richard B. Mulvany It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, lines 53 and 54, cancel "expandable" and lnsert the same after "said" in line 54, same column Signed and sealed this 26th day of August 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, J r.

Attesting Officer Commissioner of Patents 

